SORT return value lost with (space 0) on specialized vectors

[Eric Marsden]

Hi,

From random-integer testing on Linux/AMD64:

* (lisp-implementation-version)
"2.4.4.142-065494fec"
* (defun foobles (a)
    (declare (optimize (speed 2) (space 0)) ; (space 0) important
             (type (vector (unsigned-byte 7)) a)) ; fails for all sorts of specialized vectors
    (sort a #'<))
* (foobles (coerce (vector 1 2) '(vector (unsigned-byte 7))))
NIL ; <-- expecting #(1 2)

(sbcl-devel is refusing my emails but I see that the issue has been reported)